How do we grow from a single fertilized egg into an adult person with trillions of cells? Of course, our cells divide!
And it is no small matter. Each time a cell divides, it has to duplicate our 23 chromosome pairs and make sure each "daughter" cell ends up with a complete set of genes.
Errors can be life-threatening for the cell. The out-of-control cell division, which is the hallmark of cancer, is also a serious matter.
No wonder, then, that biologists have long been studying cell division when they know about cells.
Over the years, scientists have compiled a coherent history of how the process evolves. And now, the nonprofit Allen Institute in Seattle has used this knowledge to create a visualization of human cell division that is suitable for both professional scientists and curious amateurs. (The above computer-aided visualization shows the anaphasic stage of cell division.)
The institute's model follows the fate of 15 different parts of the cell, from the chromosomes themselves to the tiny fibers, the microtubules, that help pull the chromosomes apart during cell division. (The model focuses on the type of cell division called mitosis and the duplication of a cell, as opposed to meiosis, the cleavage that leads to egg and sperm cells.)
The result is 75 representative skin cells, says Susanne Rafelski, who works at the Allen Institute for Cell Science.
Each component has been tagged with a fluorescent tag so that its fate can be traced through the five phases of the cell cycle, starting with cell growth, DNA synthesis, another growth phase and two phases in which the cell actually divides and creates two daughter cells ,
The parts are color-coded so you can track your favorite cell component as the data merges into a compound cell.
"We are interested in understanding the cell as a whole," says Rafelski. "The overall picture is that we want to put the cell back together with all the mechanistic information we've gathered over the years."
These types of visualizations are becoming increasingly popular with biologists, teachers and the curious. The Allen Institute has studied the technology that applies to the brain. The Howard Hughes Medical Institute (which is one of the financial supporters of NPR) has also created visualizations of the entire brain of a fruit fly, developed mouse embryos and a variety of other images that are aimed at science teachers.
Another pioneering achievement is the Visible Human Project, launched in 1994 and updated over the years, showing a man and a woman initially created from CT and MRI scans and ultimately based on images derived from thin slices of donated bodies , A private company has created a computer program that allows anatomy enthusiasts to explore the visible.
You can contact NPR Science Correspondent Richard Harris at email@example.com.